An EO comb generator (EO comb) is a type of signal generator which generates multiple harmonics of its received optical input signal which provides an output spectrum which resembles the teeth of a comb. Seed sources used by such EO combs include mode-locked lasers (MLLs), optically pumped micro ring resonators, and the electro-optic modulation of a narrow linewidth continuous wave (CW) laser. In the CW laser case an electrical signal from a high frequency oscillator is applied to series of EO phase and intensity modulators to generate sidebands around a single CW tone from the laser, generating coherent optical combs generally spanning several nanometers in width.
In the simplest case an EO modulation (EOM) comb can be configured using commercially available components including a CW laser, intensity and phase modulators, and an external high frequency RF source for providing a high-frequency RF driving signal. Such EOM combs have generally been used for the generation of ultrashort optical pulses. More recently EOM combs have seen more frequent use as an optical source for a broader scope of applications, such as for molecular spectroscopy and for optical frequency synthesis.